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Gender equity is imperative to the attainment of healthy lives and wellbeing of all, and promoting gender equity in leadership in the health sector is an important part of this endeavour. This empirical research examines gender and leadership in the health sector, pooling learning from three complementary data sources: literature review, quantitative analysis of gender and leadership positions in global health organisations and qualitative life histories with health workers in Cambodia, Kenya and Zimbabwe. The findings highlight gender biases in leadership in global health, with women underrepresented. Gender roles, relations, norms and expectations shape progression and leadership at multiple levels. Increasing women's leadership within global health is an opportunity to further health system resilience and system responsiveness. We conclude with an agenda and tangible next steps of action for promoting women's leadership in health as a means to promote the global goals of achieving gender equity.

Although the association between cannabis use and violence has been reported in the literature, the precise nature of this relationship, especially the directionality of the association, is unclear.

Method

Young males from the Cambridge Study of Delinquent Development (n = 411) were followed up between the ages of 8 and 56 years to prospectively investigate the association between cannabis use and violence. A multi-wave (eight assessments, T1–T8) follow-up design was employed that allowed temporal sequencing of the variables of interest and the analysis of violent outcome measures obtained from two sources: (i) criminal records (violent conviction); and (ii) self-reports. A combination of analytic approaches allowing inferences as to the directionality of associations was employed, including multivariate logistic regression analysis, fixed-effects analysis and cross-lagged modelling.

Results

Multivariable logistic regression revealed that compared with never-users, continued exposure to cannabis (use at age 18, 32 and 48 years) was associated with a higher risk of subsequent violent behaviour, as indexed by convictions [odds ratio (OR) 7.1, 95% confidence interval (CI) 2.19–23.59] or self-reports (OR 8.9, 95% CI 2.37–46.21). This effect persisted after controlling for other putative risk factors for violence. In predicting violence, fixed-effects analysis and cross-lagged modelling further indicated that this effect could not be explained by other unobserved time-invariant factors. Furthermore, these analyses uncovered a bi-directional relationship between cannabis use and violence.

Conclusions

Together, these results provide strong indication that cannabis use predicts subsequent violent offending, suggesting a possible causal effect, and provide empirical evidence that may have implications for public policy.

Increased public and institutional awareness of both the benefits and threats of nitrogen has the potential to greatly increase the efficacy of nitrogen policy.

Insufficient recognition of the financial, behavioural and cultural barriers to achieving an optimal nitrogen future risks policy antagonisms and failure.

Here we examine some of the key societal levers for and barriers to achieving an optimal nitrogen future in Europe, drawing lessons from the more-developed societal and policy challenge of climate change mitigation.

Key findings/state of knowledge

There is currently a very low level of public and media awareness of nitrogen impacts and policies. However, awareness is high regarding the threats and benefits of ‘carbon’ to society (e.g. energy use and enhanced climate change).

In achieving an optimal nitrogen future, lessons can and should be learned from existing climate change-focused communication and behavioural science (e.g. use of a ‘segmented strategy’ to reach disparate groups of stakeholders).

Key sectors where societal choice has the potential to greatly influence nitrogen use efficiency include food production, consumption and waste.

Plots in the Jamaican montane forest were fertilized with nitrogen or with phosphorus to test the hypothesis that growth of trees in this natural forest is limited by the supply of N and P from the soil.

Once a year from 1983 to 1986, urea was added to one plot (at 150 kg N ha−1 y−1) and triple superphosphate was added to another (at 50 kg P ha−1 y−1). In each of these plots and in two control plots, foliage of four common tree species was collected immediately before each fertilizer addition. Trunk growth was measured in 105 individuals.

Foliar N concentrations were not significantly higher in trees fertilized with N compared to control trees. In Dendropanax cf. pendulus and Hedyosmum arborescens fertilization with N resulted in lower P concentrations but only after the third year of fertilization, possibly due to dilution by increased leaf production. Mean trunk diameter growth was significantly higher in the N-fertilized trees than in controls.

Mean foliar P concentrations were higher in Podocarpus urbanii and Clethra occidentalis following fertilization with P, but only after two years of fertilization. Trunk diameter growth was greater in the P fertilized plot.

Thus growth in some Jamaican montane forest trees was limited by the natural supplies of N and of P.

1. The gneiss of the Sikait-Zabara district is in its mineral composition an aplitic granite, which has been subjected to intense pressure. It formed part of a magma of granitic composition which invaded a series of serpentines, themselves altered peridotites. The biotite-schist in many places immediately overlying the gneiss is the direct result of the assimilation of parts of the ultrabasic Tocks by the intrusive magma, the quartz, beryl, fluorite, tourmaline rock, and talc-schists associated with the biotite-schist bearing itness to the accompanying pneumatolytic action and silicification.

2. The schist from Kosha in the North Sudan most nearlyresembles the acid gneiss of Wadi Shalul in the Eastern Desert of Egypt. If the latter were originally a granite, as has been suggested from the analysis, then the Kosha schist would itself be an intensely crushed granite containing potash and soda in approximately equal amount.

3. The schist from opposite Khor Abdel Rahman in the North Sudan has been classified as fine-grained, epidote-albite-gneiss of uncertain origin.

4. The schist between Khors Abu Dom and Sila in the North Sudan has been compared with the rock from the Lewisian formations of Coll in Scotland. It may be termed a hornblende-granulite,representing an extreme case of metamorphism with crystallization under great stresses of an originally sedimentary rock.

5. The green schist from the Wadi Um Selman ravine, near the Dm Garaiat gold mine in South-East Egypt, is also regarded as an epidote-albite-gneiss, the bands being alternately quartzose and epidotic. The lime-containing minerals originally present have been altered to epidote and calcite.

6. The rock from Da'aba Island, in the Second Cataract, is an oligoclase-mica-diorite-porphyry, the felspar having been proved to be more acid than originally concluded. This name has therefore to be adopted in place of labradorite-dolerite, the term applied to it in pi. lxxx of Hume's Geology of Egypt, ii, p. i, 1934.

7. The rock of Arkasa Island, also from the Second Cataract, is, judging from the analysis, probably a more acid form of the oligoclase-mica-diorite-porphyrite series.

8. The specimens Nos. 8 to 11 represent a group of rocks in which magnesite plays an interesting part in the composition.

While No. 8 from Wadi Haimur is in the main a serpentine with but little magnesite, the remaining three rocks contain a notable percentage of this mineral. Pending further investigation, it is suggested that these changes may have taken place during periods when the ancient peridotites were submerged beneath the waters of the sea at various times in the geological history of Egypt.

Dr. Hume desires to thank Mr. 0. H. Little, Director of the Geological Survey of Egypt, very warmly for having left Mr. A. I. Awad free to carry out the petrographical studies for this paper whenever circumstances allowed of his doing so. This paper is published with the approval of H.E. the Surveyor-General of Egypt.

The detailed dynamics of the Solar dynamo presents a significant challenge to our understanding of the interaction of convection and magnetic fields in the Solar interior. In this paper we discuss certain aspects of this interaction, such as modification of convective energy transport, and turbulent dissipation of magnetic fields. The latter controls the spatial distribution of the magnetic field and its time dependence. We also discuss how these results may influence current Solar dynamo calculations.

MOTIVATION

Solar activity manifests itself in many forms but perhaps most importantly through the presence of a magnetic field. The topic of this meeting is that of dynamos, in Solar and planetary contexts. In the case of the Sun the dynamo, which seems likely to be responsible for at least part of the Solar activity we observe, acts on a global scale. That is, the period of the dynamo is 22 years (a timescale distinct from those usually encountered on the Sun), sunspots appear within latitude bands and their numbers (in terms of monthly or yearly running means) increase and decrease over one cycle. There is however, a strong asymmetry of the Solar cycle in time, i.e. the growth phase is shorter (and dependent of the amount of activity) than the decay, or descending phase. In addition, the polar field of the Sun is observed to reverse around Solar maximum, again with a distinct asymmetry between hemispheres. Despite these global-scale features, the Solar magnetic field has many spatial components (Stenflo 1991) and the majority of the magnetic flux appears in small elements.

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